With the proliferation of the Internet and the World Wide Web (the “Web”), search engines have become an invaluable tool to locate information. A user can submit a request for information (commonly referred to as a “query”) to a search engine, which then searches for web content related to the request. Search engines search for query terms, or combinations thereof, in content on the Web. When terms are found in web content, the web content is presented to the user in a results list.
A significant portion of user queries do not produce search results because web content containing the query terms cannot be found. These queries are commonly referred to as “no-result queries.” No-result queries typically contain unique terms that have never or rarely been submitted to the search engine. Additionally, many no-result queries contain misspellings and are relatively large, making them too specific to produce results.
To make query results more accurate, modern search engines have become sophisticated enough to spell check query terms and recommend related query terms and phrases to guide the user. As a result, the user can refine a search-engine query to terms that more accurately reflect the user's intended request. Related query terms are typically generated by a search engine mapping a single query term to a set of query suggestions. Two common approaches are used to map query terms. In the first, common queries that contain the original query words are identified from search-engine log data, which includes historical data associated with other users' queries. In the second, search-engine log data is analyzed to determine how users, in aggregate, have historically refined their original queries. Both approaches, however, require common queries that have been submitted previously and appear in search-engine data logs. Consequently, these refinement techniques cannot be used to enhance no-results queries because no-results queries have typically not been previously submitted to the search engine, and therefore are not included within search-engine log data.